Parse /etc/lsb-release only once on ChromeOS

chrome/browser/chromeos/external_metrics.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/external_metrics.h"
 
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 82 matching lines @@
               << name_of_experiment << " field trial";
   } else {
     LOG(ERROR) << "Couldn't write to " << group_file_path.value();
   }
 }
 
 // Finds out if we're on a 2GB Parrot.
 //
 // This code reads and parses /etc/lsb-release. There are at least four other
 // places that open and parse /etc/lsb-release, and I wish I could fix the
 // mess.  At least this code is temporary.

[Daniel Erat, 2013/09/24 15:37:53]

nit: delete this outdated comment

[stevenjb, 2013/09/24 17:18:34]

Done.

 
 bool Is2GBParrot() {
-  base::FilePath path("/etc/lsb-release");
-  std::string contents;
-  if (!base::ReadFileToString(path, &contents))
-    return false;
-  if (contents.find("CHROMEOS_RELEASE_BOARD=parrot") == std::string::npos)
+  if (base::SysInfo::GetLsbReleaseBoard() != "parrot")

[Daniel Erat, 2013/09/24 15:37:53]

this code makes me sad.

(probably not your fault.)

that is all.

[stevenjb, 2013/09/24 17:18:34]

Yeah... at least we're not doing an extra file read now (even if this is on the
IO thread).

     return false;
   // There are 2GB and 4GB models.
   return base::SysInfo::AmountOfPhysicalMemory() <= 2LL * 1024 * 1024 * 1024;
 }
 
 // Sets up field trial for measuring swap and CPU metrics after tab switch
 // and scroll events. crbug.com/253994
 void SetupSwapJankFieldTrial() {
   const char name_of_experiment[] = "SwapJank64vs32Parrot";
 
@@ skipping 291 matching lines @@
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   // Field trials that do not read from files can be initialized in
   // ExternalMetrics::Start() above.
   SetupProgressiveScanFieldTrial();
   SetupSwapJankFieldTrial();
 
   ScheduleCollector();
 }
 
 }  // namespace chromeos